It is known to subject yarns, for example after twisting or after cabling, to a thermal treatment and to thus achieve an improvement in the yarn quality. A thermal treatment of this type stabilizes the state of the yarns after the twisting or cabling and frees the yarns from inner torsional forces. Moreover, a thermal treatment of this type leads to a shrink bulking of the yarns, which brings about an increase in the volume of the yarn.
Various methods and mechanisms for the thermal treatment of yarns are described in the patent literature. It has been known, for a long time in this connection, for example, to send yarn wound on bobbins or cops in batches for thermal treatment into steam systems, so-called autoclaves and to thus simultaneously set a large number of bobbins or cops. These known setting devices, however, have the drawback that they require a relatively large amount of space and are also comparatively expensive to acquire. Moreover, qualitative losses of the yarn treated can often not be avoided in these setting devices.
Furthermore, yarn treating devices are known, which are arranged directly in the region of the workstations of twisting machines and with which setting can be carried out on the traveling yarn. There has been success in making the setting process of yarns more economical and efficient using yarn treating devices of this type described, for example, in European Patent Publication EP 1 348 785 A1 or in German Patent Publication DE 103 48 278 A1.
The known devices generally in each case have a yarn treating chamber, into which a gaseous or steam-like treating medium under pressure is blown, the subsequent process of cooling leading to the setting of the yarn. Yarn treating chambers of this type are also equipped with opposing yarn inlet and yarn outlet openings, in the region of which respective sealing devices are installed which seal the yarn treating chamber relative to the environment.
The yarn treating device described in European Patent Publication EP 1 348 785 A1, for example, has sealing devices, which have various rollers, with which pressure losses being produced when the yarn is running into or out of the yarn treating chamber are to be minimised. These sealing devices preferably have drivable outer sluice rollers and inner sealing rollers, which are in each case equipped with a resilient plastics material ring, into which the yarn is pressed when passing the sealing devices.
However, the comparatively wear-sensitive plastics material rings of the sealing rollers are disadvantageous in these sealing devices. The relatively short service life of the plastics material rings requires short service intervals, which has a very negative effect on the efficiency of the yarn treating device.
A yarn treating device is described in German Patent Publication DE 103 48 278 A1, in which the yarn treating chamber, in the region of its yarn inlet and yarn outlet opening, in each case has a yarn sluice with wear-resistant yarn guide elements. In a first embodiment of the yarn sluice, the latter is equipped with two identical, in each case semi-circular, yarn guide elements, which are pressed against one another by a spring element and have, in the region of a common centre longitudinal axis, recesses which form a yarn guide channel. The cross-section of the yarn channel is, in this case, precisely matched to the mean thickness of the yarn to be treated, in other words during operation, the yarn guide channel is sealed by the traveling yarn. When there is a yarn thickening, the yarn guide elements are pressed outwardly against the force of the spring element, so the yarn with the yarn thickening can also pass through the yarn sluice.
In a further embodiment also described in German Patent Publication DE 103 48 278 A1, the yarn guide elements of the yarn sluice are configured in such a way that one of the yarn guide elements is rotatably mounted in the manner of a revolver. In other words, by corresponding positioning of the rotatably mounted yarn guide element, the cross-section of the yarn guide channel can be adjusted. The configuration and arrangement of the yarn guide elements in this case allows a selection to be made between four different cross-sections of the yarn guide channel. In this embodiment as well, one of the yarn guide elements, preferably the rotatably mounted yarn guide element, is arranged in such a way that it can move aside when a yarn thickening occurs.
However, it is disadvantageous in the known yarn sluices that adaptation of the cross-section of the yarn guide channel to the respective thickness of the yarn is often relatively complex or an exact adaptation of the cross-section of the yarn guide channel to the respective yarn diameter is frequently not possible. In other words, in the first embodiment, in the event of a batch change, in which a change is made to a yarn with a different mean thickness, the yarn guide elements also generally have to be replaced, in other words, the installed yarn guide elements have to be replaced in a time-consuming manner by new yarn guide elements which fit the mean thickness of the new yarn.
In the second embodiment as well, in which a selection can be made by the rotatably mounted yarn guide element between four yarn guide channel sizes, difficulties can occur when the yarn has a mean thickness which does not correspond precisely to one of the adjustable yarn guide channel sizes. In other words, in a case such as this, problems are also often produced with regard to a proper sealing of the yarn treating chamber. It has moreover been shown that with the known yarn sluices, in particular with yarn sluices with a rotatably mounted yarn guide element, difficulties occasionally occur when yarn thickenings run through, because, for example, the mounting of the rotatably mounted yarn guide element cannot react sufficiently resiliently to yarn thickenings of this type. Difficulties of this type often result in damaging tensile force increases and problems in the sealing of the yarn guide channel.